SQL query: Simulating an “AND” over several rows instead of sub-querying

Question

Suppose I have a \"tags\" table with two columns: tagid and contentid. Each row represents a tag assigned to a piece of content. I want a

Answer 1

The only alternative way i can think of is:

select a.contentid from tags a
inner join tags b on a.contentid = b.contentid and b.tagid=334
inner join tags c on a.contentid = c.contentid and c.tagid=342
where a.tagid=338